The idea is simple: iTunes scans your music library, sends the information about your songs to Apple’s servers, and then either “matches” music that’s in both your library and the iTunes Store, or uploads the music that isn’t in the iTunes Store. Then, you can either download or stream (depending on the hardware) all of your music from a Mac or PC running iTunes 10; an iPhone, iPad, or iPod touch running iOS 5 or later; or a second- or third-generation Apple TV.

When iTunes matches your music, it scans your entire library so it can recognize its contents and send that information to Apple's servers.

In theory, iTunes Match is a great idea. The point of matching your music is to leverage the more than 26 million songs in the iTunes Store so you don’t have to upload all your music, saving you time, and saving Apple the hassle of having to store millions of copies of songs. When your music is matched, Apple keeps your specific tags and album art, but the actual music files aren’t duplicated. And if the matched file is of better quality than your original—iTunes offers 256-kbps AAC files, but will recognize the 128-kbps MP3 you ripped from a CD a decade ago—you can replace your aging copies with pristine iTunes Store music.

In practice, however, everything doesn’t work as well as it should in the realm of iTunes Match, with users facing a number of hiccups and difficulties since the service’s inception. With renewal notices going out to those who signed up early on, it will be interesting to see how many people pony up for another year.

iTunes Match problems

Since day one, there have been a number of problems with iTunes Match. Some are mildly annoying, some are frustrating, and others are simply insurmountable. Here are some of the most common problems with iTunes Match.

Songs don’t match: The number of songs that don’t match is surprising. In many cases, eight or nine songs on an album will match, but one or two won’t. And this is for music sold by the iTunes Store, so there’s no reason for these songs to not be recognized. Macworld Senior Writer Lex Friedman conducted an unscientific survey last year of how many people tried to match the Beatles’ Abbey Road, and found that one song, “She Came In Through the Bathroom Window,” wouldn’t match for just about everyone. (Curiously, my copy of the song did match.) This flaw is both frustrating and time-consuming, as it requires you to upload more of your music. And if you use iTunes Match to upgrade your songs to higher quality, it’s not ideal to have most of an album match and a few songs not.

Even for purchased tracks, some don't match and end up getting uploaded. On this album, purchased from the iTunes Store, two tracks are not recognized as purchased, and one isn't even matched.

iTunes Match has a 25,000-song limit: While this limit doesn’t include any music you purchase from the iTunes Store, it’s still a problem for music fans with big libraries. Some may dismiss the complaint as irrelevant to those who aren’t music pirates, but large libraries are more and more common among law-abiding music lovers. Also consider that Amazon’s Cloud Player Premium service offers a similar matching/uploading package, but has a 250,000 track limit—ten times as much as Apple's—at the same yearly price.

Explicit songs replaced with clean versions: Many people who purchased explicit versions of songs find that, when they later redownload those songs from iTunes, they get the clean versions instead.

Problems with playlists: Many users of iTunes Match have problems with playlists that don’t sync, that duplicate, that display in the wrong order, and more. And there’s no way to fix this, short of turning off iTunes Match and turning it back on again. And even that doesn’t always resolve the problem.

Tags don’t work right: Another common problem has to do with tags, lyrics, and artwork. Users may change tags on a Mac and find that the changes don’t propagate to iTunes Match. When people change artwork on their computer, it’s not reflected on new downloads to their iPhone. Lyrics disappear, play counts and last-played dates don’t update, and more.

iOS 6 changes make it harder to use: With iOS 6 came two major changes to iTunes Match. First, you can no longer delete music from your iOS device. As Apple says, “When iTunes Match is turned on, you can’t delete music. If space is needed, iTunes Match removes music for you, starting with the oldest and least-played songs.”

Second, there are no longer cloud icons next to each song, meaning that you can’t know if you have a song on your iOS device or not. If you go to play it, and find that you’re downloading something, it will count against your cellular data plan if you’re not on a Wi-Fi network. (You can choose to display only music that is on the device, in Settings > Music. But then you won’t see other music that you might want to download.)

Some possible fixes for iTunes Match

As you can see, a lot of things need to be fixed for iTunes Match to work as it should. I've mentioned only the most egregious problems, but there are plenty of others. Here are some suggestions for how iTunes Match can be fixed.

Have too many tracks? Then you need not apply for iTunes Match.

Overhaul how iTunes Match deals with tracks and limits: Apple should take Amazon’s lead and increase the track limit for iTunes Match users at least a bit. Bump it to 35,000, say, and then let people pay extra if they need more. iCloud already has tiers for extra storage, so this is nothing new for Apple (although, to be fair, there may be some complications with record labels and royalties).

At the same time, Apple should offer a checkbox or other option to indicate which tracks you want to match/upload. I was disappointed to find that I couldn’t even sign up for iTunes Match because my library was too large. I created a second, smaller library on my laptop that I use with iTunes Match, but I shouldn’t have to. Apple needs to provide better options if it’s going to limit tracks the way it does.

Let users choose which tracks they match and which they just store on their computers.

Let users rematch their music: For all those albums where one or two tracks don’t match, Apple should improve its matching algorithm, or even provide a way for users to choose tracks in the iTunes Store that match. (Obviously iTunes would have to scan the tracks to see if they’re the same.) And if users haven’t deleted their originals, provide a Do Over command to attempt a rematch. My guess is that Apple has been improving the match algorithm—and that we may even see the result in iTunes 11, due later this month.

Fix the playlist problems: This one is on you, Apple. Many users spend a lot of time creating playlists to organize and listen to their music, and if you break the playlists, it becomes a headache for people to find their songs. Apple says: “When you create, edit, or delete a playlist on your Mac, PC, iPhone, or iPad, those changes will sync across any iTunes Match-enabled device you own.” Playlists should simply sync perfectly via iTunes Match, and for many users they don’t.

Fix the explicit/clean download problem: As mentioned, mixing up explicit and clean versions needs to be addressed. At the same time, please fix the problem where, in some cases, an edited version (such the single version) or a live version of a song gets downloaded instead of the version the person actually had.

When iTunes Match works, it works very well. But when it doesn’t work, the frustration is enough to make users throw up their hands, give up, and go back to the old way of syncing music and copying it from one computer to another. Users shouldn’t have to deal with the kinds of problems that we’ve seen, and their music libraries should sync correctly to the cloud, and to other devices. Please, Apple, make this work; iTunes Match is too good an idea to fail.